This investigation focuses on the effects of cold exposure on airway mechanics in normal man and in patients with airway diseases. The proposed studies are designed to: 1) characterize the pulmonary mechanical and ventilatory response to cold exposure in normals and in patients with lung disease; 2) determine the mechanism by which cold exposure produces respiratory effects; 3) explore whether cold alters ventilatory patterns and/or airway temperatures, and so changes the manner in which the air is heated and humidified; and 4) determine if there is an association between responsivity to cold air and abnormalities in autonomic function. To achieve these goals, we propose a series of integrated studies in normals and patients with asthma and chronic bronchitis. In the first set of studies, we will have patients sit in a -10 degrees C room while we monitor pulmonary mechanics. The next task will be to isolate the stimuli. Using the same subjects, we will apply cold first to the body and then the airways. In both situations stimulus-response curves will be generated. In another set of experiments, we will see if cold applied to the skin amplifies the effects of cold applied to the airways during resting breathing and when ventilation is increased. We will also see if cold on the skin and in the airways influences the responses to other constrictor agents, along with examining the effects of such drugs as lidocaine, atropine, and cromolyn. The second major set of experiments is designed to determine if cold exposure alters airway temperatures directly or by changing the pattern or level of ventilation. We plan to use a specially designed thermal probe to measure interairway temperatures in our subjects before, during and after exposure of their skin to cold air. A subset of these experiments will also be performed to determine if exposure to cold increases nasal resistance causing a shift from nasal to oral breathing. Finally, we propose to examine autonomic function as assessed by lymphocyte beta-adrenergic responses and pupillometry in subjects with increased responsiveness to cold air. These studies will help identify mechanisms by which cold produces respiratory symptoms, identify risk factors in patients and will be useful in devising and evaluating therapeutic interventions.